Bioengineers and physicians working at Cornell have created an artificial ear using a combination of 3-D printing and injection molds. According to the scientists, the bioprinted ear looks and acts like a natural ear giving hope to thousands of children born with a congenital deformity called microtia.

The researchers recently described how their 3-D printing method combined with injectable gels made from living cells were able to create ears that over a three-month period grew cartilage to replace the collagen used to mold them.

"This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together," said co-lead author Lawrence Bonassar.

"A bioengineered ear replacement like this would also help individuals who have lost part or all of their external ear in an accident or from cancer," said co-lead author Doctor Jason Spector.

To make the new 3-D printed ears, the researchers start with a digitized 3-D image of a human subject ear. That image is then converted into a solid ear using a 3-D printer to assemble the mold. The researchers then inject a high-density gel into the mold, while collagen in that gel serves as a scaffolding allowing cartledge to grow.

According to Bonassar, the mold can be designed in roughly half a day, and it takes just 30 minutes to inject the gel. The new ear can be removed from the mold 15 minutes later and trimmed to shape. At that point, it takes another few days for the ear to culture before it can be implanted into the human subject.

The replacement ear doesn't contain nerves. It's intended to restore the same functionality and appearance as a real ear. The functionality is important - ears have a common specific shape for a good reason. The appearance is secondary but also important. It's not easy to replace an ear with an artificial lookalike. The ear is on the side of your head and firmly anchored there with no protrusions. You'd have to break the skin cover or tie it around the head so this is a big deal.

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